The present invention relates to connecting electronic interface cards into a mobile station.
Nowadays, in mobile stations, to identify the subscriber it is common to use an interface card SIM (Subscriber Identification Module), which also usually contains non-volatile memory to store e.g. phone numbers. SIM-card comes in two standardised sizes, of which the smaller SIM-card is about 25 mm long, 14 mm wide and less than 1 mm thick, and its surface contains conductive surfaces arranged in a certain way. A mobile station using a SIM card has e.g. spring-loaded contact pins that form an electric contact with necessary contact surfaces and by using which the mobile station can electrically transmit information to the SIM-card and back to its own memory. A SIM-card comprises a control unit (CPU, Central Processing Unit), program memory (ROM, Read Only Memory), data memory suitable for long term storage (EEPROM, Electrically Erasable Programmable Read Only Memory) and data memory suitable for runtime storage (RAM, Random Access Memory). Using the mobile station requires keying in a personal identification number stored in a SIM-module when using the phone, most usually when switching the mobile station on. The data memory of the SIM-module can be used to store also other user-specific data such as phone numbers or messages etc.
Due to the rapid development of information technology, new mobile stations will contain an increasing number of computer-like features. They need more and more so-called RAM-memory (Random Access Memory) to serve as working memory, and peripheral devices familiar from microcomputers will possibly be also used in mobile stations. However, mobile stations are often required to be designed and manufactured so small and light that the user can transport them whenever he/she likes, e.g. in a belt pouch. In this case the solutions known from portable microcomputers easily lead to too large a size and too high a weight for use, and that is why Nokia Mobile Phones Ltd. has brought out to market a new mobile phone model called Nokia 9110 Communicator, which combines a portable computer and a mobile station into a compact unit. This device is capable of using new multimedia cards (SanDisk MultiMediaCard) to increase the working memory of the device. Additionally programs or e.g. the own telephone catalogue of the firm can be stored on the multimedia card. Below the SanDisk multimedia card will be referred to with the abbreviation MMC-card. The length of MMC-card is 32 mm, width 24 mm and thickness 1,4 mm. For these cards the Nokia 9110 Communicator contains a separate interface card slot, where the MMC-card can be placed.
In the future a second small SIM-card can be attached to mobile stations. With two SIM-cards the user can use the services of two different mobile communication networks. However, the second SIM-card requires its own interface card slot. If the mobile station also contains an interface card slot for an MMC-card, it will need three different interface card slots. Every interface card slot yet requires its own space and means for using the cards attached to it. In addition to different purpose, the physical measurements, grouping of contact surfaces and operating voltages of SIM- and MMC-cards are different.
A connecting device with which different sizes of interface cards can be used is known from patent publication U.S. Pat. No. 5,336,877. The publication presents an invention, where a small SIM-card is aligned with a separate adapter so that its contact surfaces connect with the contact pins meant for using larger interface cards. However the contacts have to be in the same order with respect to their purpose of use and their pitch has to be corresponding, even though it seems possible to connect a card that lacks a part of the contacts of the larger card into the device according to the publication. The purpose of the invention according to the publication is indeed to adapt two different types of phone cards to be used in the same phone.
Now a mobile station has been invented, which mobile station comprises an interface card slot, which can be used to connect alternatively a small SIM-card or a Sandisk MMC-card to the mobile station. The mobile station has means for physically and electrically adapting a small plug-in SIM-card known from the GSM to an interface card slot for an MMC-card and of the size of MMC-card""s, in order to be used as a SIM-card when the MMC-card is not present in the interface card slot. Furthermore, the mobile station has means for making the mobile station use the SIM- or MMC-card currently present in the interface card slot in a way akin to the use of that card in said interface card slot.
An interface-card slot of a mobile station, according to the present invention, comprises mechanical support for holding in place, during the normal use of the mobile station an at least partially inserted SIM- or MMC-card. Additionally, the mobile station comprises connecting means to connect the used contact surfaces of the current interface card with the mobile station""s electronics controlling and using the interface card. Connecting means comprise at least contact devices corresponding to the grouping of an MMC-card""s contact surfaces in order to connect an MMC-card and, in certain embodiments, a group of contact devices in order to connect a SIM-card""s contact surfaces into the mobile station. In these embodiments part of or all SIM-card""s contact surfaces can optionally be connected through contact devices meant for MMC-cards e.g. by using and adapter card changing SIM-card into the size of MMC card and comprising a group of contact surfaces conforming to the grouping of the contact surfaces of an MMC-card. In this case a mobile station also comprises means for identifying the current interface card in order to identify an operating voltage suitable to the current interface card and to route the connection of the contact surfaces of the interface card in such a way that the mobile station can use the interface card. An interface card slot according to a first embodiment of the present invention comprises separate contact pins for using SIM- and MMC-cards. A part of the contact pins of a mobile station""s interface card slot according to a second embodiment of the present invention are common i.e. multiplexed. All of the contact pins of a mobile station""s interface card slot according to a third embodiment of the present invention are common i.e. multiplexed and the contact surfaces of a SIM-card are made to correspond the grouping of the contact surfaces of an MMC-card by means of an adapter.
According to a first embodiment of the present invention a mobile station is provided, comprising
an interface card slot for using an MMC-multimediacard (SanDisk MMC-MultiMediaCard), which MMC-card comprises, on it""s outer surface, a first group of grouped contact surfaces for data transfer and power supply;
a first voltage supply to give a defined first voltage;
a data transmission means for reading data from an MMC-card and for writing data on an MMC-card;
and which interface card slot comprises:
walls defining a first space receiving at least partially an MMC-card, and
a first attaching means for attaching an MMC-card detachably to said space;
a first connecting means for connecting a first voltage to a certain contact surface of an MMC-card;
a second connecting means for connecting the data transmission means to a certain contact surface of the MMC-card, wherein the mobile station further comprises:
a second attaching means for attaching a SIM-card to said first space, which SIM-card has a grouped second group of contact surfaces;
a second voltage supply for giving a defined second voltage;
a third connecting means for connecting said second voltage into a certain contact surface of the SIM-card;
a fourth connecting means for connecting said data transmission means to a certain contact surface of the SIM-card.
A mobile station according to a second embodiment of the present invention is characterised in that the mobile station comprises
an interface card slot for swappable interface cards of mechanically and electrically two types, for interface cards of a first and a second type, which interface cards have a certain size, use and contact surfaces grouped in a certain way according to their type, where the size, use and grouping of contact surfaces of these interface cards deviate from each other,
a first contact device for making contact with the contact surface of an interface card of the first type,
a second contact device for making contact with the contact surface of an interface card of the second type,
a means for attaching an interface card of the first type detachably into the interface card slot,
a means for attaching an interface card of the second type detachably into the interface card slot, and
a means for indicating the type of the interface card to the mobile station based on the difference between the interface cards, in order to allow the mobile station to use the interface card attached to it.
For a method according to the present invention, where the interface card slot of a mobile station is mechanically and electrically adapted to fit two types of replaceable interface cards and the size and the grouping of contact surfaces of these interface cards deviates from each other, characterised in that
an interface card of first or second type attaching to the interface card slot,
interface cards of the first type are connected to the mobile station by using a first group of contact devices,
interface cards of the second type are connecting to the mobile station by using a second group of contact devices, and
the type of the current interface card indicating to the mobile station so enabling the mobile station to use the interface card connecting it.